This invention relates to a method for manufacturing solid drug delivery ophthalmic inserts. More particularly, the method involves the preparation of rod shaped inserts used for the treatment of dry eyes and ophthalmic diseases by forming a paste gel by the addition of controlled increments of water to a hydrophilic water soluble polymer.
Conventional ophthalmic drug delivery methods utilize liquid drops, ointment or suspension type installation in order to evoke the desired therapeutic response. Although effective in treating ocular diseases, these methods have specific disadvantages. A patient may lose a substantial portion of the medicine due to poor delivery technique or to involuntary tearing following installation. Additionally, many patients may not adhere to the physician's prescribed regimen for daily treatment. Furthermore, if drug delivery is required more than once or twice a day, the patient may be inconvenienced while away from home.
A more recent development relates to a water soluble solid ophthalmic insert for the treatment of dry eyes composed of a water soluble polymer of appropriate size which can be placed in the cul-de-sac of the eye. The insert is prepared by completely dissolving particles of the polymer in water and subsequently evaporating all the water in order to form a solid insert.
However, this method does not produce a sufficiently sustained therapeutic response for the treatment of various eye diseases. Since inserts of water soluble solid polymer are formed by completely dissolving the starting drug particles in excess water, significant amounts of water are retained by the dosage form even after drying. Additionally, if the shape of the inserts is circular and dimensionally thin, a large surface area remains in contact with the lacrimal fluid in the eye after application. These features contribute to rapid dissolution and release of the product when treating eye disease.
Accordingly, it is desirable to provide an improved method for ophthalmic drug delivery having a more prolonged and sustained delivery of the required medicinal dosage.